The oligomerization of ethylene to produce hexenes and/or octenes in a homogeneous process often can produce a by-product stream containing an ethylene-based polymer. In some circumstances, the polymer produced can cause reactor fouling, and associated costs, clean-up, and downtime. It would be beneficial to produce hexenes and/or octenes from ethylene using a process that is less susceptible to reactor fouling and its related drawbacks. Accordingly, it is to these ends that the present invention is directed.